A biomimetic flexible composite drag-reducing coating and a preparation method thereof

Abstract

The application relates to a kind of bionic flexible composite drag reduction coating and a preparation method thereof, and belongs to the field of underwater drag reduction coating.The bionic flexible composite drag reduction coating comprises water-based epoxy resin emulsion, high molecular polymer, curing agent and additive.The mass ratio of water-based epoxy resin emulsion, high molecular polymer and curing agent is (40-100):(1-20):(5-25).The application can reduce the sailing resistance of a vehicle, thereby achieving speed increase, energy saving and consumption reduction.The application solves the problem of environmental pollution caused by current bionic drag reduction coating, and has the characteristics of excellent drag reduction effect, green environmental protection and simple preparation process.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of underwater drag reduction coating, and particularly relates to a bionic flexible composite drag reduction coating and a preparation method thereof. BACKGROUND

[0002] The main resistance of an object in a fluid is differential pressure resistance, wave-making resistance and frictional resistance, among which the frictional resistance plays a major role in the movement of the object. With the increasing competition in the ocean, the comprehensive performance of the watercraft needs to be further improved, and reducing the frictional resistance of the watercraft has great engineering significance in improving the speed, increasing the voyage and saving energy.

[0003] For a moving body in the ocean, the body of a fish is streamlined and covered with mucus, and can quickly swim under the action of buoyancy in water. Many workers are inspired by the drag reduction principle of the body surface of a fish to carry out drag reduction work, and the watercraft is designed to be streamlined, but still cannot meet the requirements of people on the speed of the watercraft, and the bionic drag reduction coating becomes a research hotspot.

[0004] The bionic drag reduction coating disclosed at present introduces heat-conducting nanosheets with a long chain segment of a hydrophilic charged group into an elastic polyurethane layer to make the coating have the properties of elasticity, heat conduction and hydrophilicity. The preparation method is to first prepare a functional group A, a prepolymer B and an additive C, and then mix and solidify them in a certain proportion to obtain a long-acting composite drag reduction coating. However, a large amount of volatile organic compounds such as ethyl acetate, toluene and isopropyl alcohol are used as solvents in the preparation process of the coating, which seriously harms the atmospheric environment and human health. Therefore, the existing technology has the problems of environmental pollution, harm to human health and complicated preparation process. SUMMARY

[0005] The technical problem to be solved is:

[0006] In order to avoid the shortcomings of the prior art, the application provides a bionic flexible composite drag reduction coating and a preparation method thereof, which can reduce the drag of the watercraft, thereby achieving speed increase, energy saving, and thus solving the problem of environmental pollution of the bionic drag reduction coating, and having the characteristics of excellent drag reduction effect, green environmental protection and simple preparation process.

[0007] The technical scheme of the application is: a bionic flexible composite drag reduction coating, comprising a water-based epoxy resin emulsion, a high molecular polymer, a curing agent and an additive, wherein the mass ratio of the water-based epoxy resin emulsion, the high molecular polymer and the curing agent is (40-100):(1-20):(5-25).

[0008] The further technical scheme of the present application is that the water-based epoxy resin emulsion is a water-based dispersion liquid formed after emulsification treatment with epoxy resin as the main component, which is a milky white uniform fluid with a density of 1.05 g / cm3, a VOC content of 0 g / L, and a particle size of less than or equal to 0.3 microns.

[0009] The further technical scheme of the present application is that the high molecular polymer is one or more of polyacrylamide, guar gum, tragacanth gum, locust bean gum and gum arabic, and the particle size is 125-170 microns.

[0010] The further technical scheme of the present application is that the curing agent is a water-soluble modified epoxy polyamine adduct curing agent, water is used as a diluent, and there is no alcohol ether solvent or cosolvent, the viscosity at room temperature is 6500-9000 mPa·s, and the density is 1.05-1.08 g / cm3.

[0011] The further technical scheme of the present application is that the auxiliary agent is one or more of leveling agents, film-forming aids, defoaming agents, dispersants, thickening agents and wetting agents.

[0012] A preparation method of a biomimetic flexible composite drag-reducing coating, the specific steps are as follows:

[0013] Step 1: slowly add the weighed high molecular polymer into the beaker containing water, and stir until all the high molecular polymer is completely added; then add the weighed curing agent into the beaker, and continuously stir to make the high molecular polymer and the curing agent fully undergo ring-opening reaction, so that the high molecular polymer is grafted onto the curing agent;

[0014] Step 2: add the weighed water-based epoxy resin emulsion and auxiliary agent into the beaker, and stir until the water-based epoxy resin and the curing agent are uniformly mixed;

[0015] Step 3: divide the uniformly stirred mixture into centrifuge tubes, and use a centrifuge to remove particles and impurities, thereby obtaining the biomimetic flexible composite drag-reducing coating.

[0016] The further technical scheme of the present application is that the stirring speed of the high molecular polymer added into water is 400 r / min.

[0017] The further technical scheme of the present application is that the stirring speed of the curing agent added into water containing the high molecular polymer is 100 r / min, and the stirring time is 1 hour.

[0018] The further technical scheme of the present application is that the stirring speed of the water-based epoxy resin emulsion and the auxiliary agent added into the beaker is 100 r / min, and the stirring time is 1 hour.

[0019] Application of a biomimetic flexible composite drag-reducing coating to the surface of a vehicle to reduce the drag of the vehicle.

[0020] Advantages

[0021] The present application has the advantages that:

[0022] The present application uses water as a solvent, avoiding the use of organic solvents such as alcohols, ethers and xylene in conventional drag-reducing coatings. In addition, the present application uses water-based epoxy resin as a film-forming material and water-soluble modified epoxy polyamine adduct as a curing agent, with a VOC content as low as 0. The present application uses materials and solvents with low VOC content to solve the problems of high VOC content, air pollution and harm to human health in traditional solvent-based drag-reducing coatings.

[0023] The present application uses a modified material as the high polymer molecule, which is grafted onto the water-based epoxy resin curing agent through a co-mixing grafting copolymerization reaction. After the coating is cured, the high polymer on the surface of the coating comes into contact with the flow field, making the coating surface exhibit pseudoplasticity and thus achieving drag reduction. The present application has a simple preparation process, which can greatly save time and labor.

[0024] The present application provides an effective mass ratio of water-based epoxy resin emulsion, high polymer and curing agent for a drag-reducing coating. An excessive amount of water-based epoxy resin emulsion may result in a low curing rate of the coating or the high polymer cannot be fully dissolved, resulting in a gel-like structure and an ideal drag reduction rate cannot be achieved. An excessive amount of curing agent may result in a low or high curing rate of the coating, and an ideal drag reduction rate cannot be achieved. An excessive amount of high polymer may result in a low drag reduction rate or a gel-like structure in the solution, which is difficult to dissolve. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 The present application provides an effective mass ratio of water-based epoxy resin emulsion, high polymer and curing agent for a drag-reducing coating. An excessive amount of water-based epoxy resin emulsion may result in a low curing rate of the coating or the high polymer cannot be fully dissolved, resulting in a gel-like structure and an ideal drag reduction rate cannot be achieved. An excessive amount of curing agent may result in a low or high curing rate of the coating, and an ideal drag reduction rate cannot be achieved. An excessive amount of high polymer may result in a low drag reduction rate or a gel-like structure in the solution, which is difficult to dissolve.

[0026] Figure 2 The present application provides an effective mass ratio of water-based epoxy resin emulsion, high polymer and curing agent for a drag-reducing coating. An excessive amount of water-based epoxy resin emulsion may result in a low curing rate of the coating or the high polymer cannot be fully dissolved, resulting in a gel-like structure and an ideal drag reduction rate cannot be achieved. An excessive amount of curing agent may result in a low or high curing rate of the coating, and an ideal drag reduction rate cannot be achieved. An excessive amount of high polymer may result in a low drag reduction rate or a gel-like structure in the solution, which is difficult to dissolve.

[0027] Figure 3 The present application provides an effective mass ratio of water-based epoxy resin emulsion, high polymer and curing agent for a drag-reducing coating. An excessive amount of water-based epoxy resin emulsion may result in a low curing rate of the coating or the high polymer cannot be fully dissolved, resulting in a gel-like structure and an ideal drag reduction rate cannot be achieved. An excessive amount of curing agent may result in a low or high curing rate of the coating, and an ideal drag reduction rate cannot be achieved. An excessive amount of high polymer may result in a low drag reduction rate or a gel-like structure in the solution, which is difficult to dissolve. DETAILED DESCRIPTION

[0028] The embodiments described below with reference to the drawings are exemplary and are intended to explain the present application, and cannot be understood as limiting the present application.

[0029] Based on the existing coating preparation process using a large amount of ethyl acetate, toluene and isopropyl alcohol and other volatile organic compounds as solvent, the atmosphere and human health have serious harm, etc.; at the same time, in view of the current drag reducing coating pollution environment, harm to human health, the defect of complicated preparation process, the present application utilizes water-based epoxy resin emulsion, polymer and curing agent of different proportion preparation, provides a kind of bionic flexible composite drag reduction coating.The bionic flexible composite drag reduction coating component includes water-based epoxy resin emulsion, polymer, curing agent, additive;Wherein, the mass ratio of water-based epoxy resin emulsion, polymer, curing agent is (40-100):(1-20):(5-25).

[0030] Specifically, the water-based epoxy resin emulsion is a water-based dispersion liquid formed after emulsification treatment with epoxy resin as the main component, which is milky white uniform fluid, the density is 1.05g / cm3, the VOC content is 0g / L, and the particle size is ≤0.3μm.

[0031] Specifically, the polymer is one or more of polyacrylamide, guar gum, tragacanth gum, locust bean gum and gum arabic, and the particle size is 125-170μm.

[0032] Specifically, the curing agent is water-soluble modified epoxy polyamine adduct curing agent, water is used as diluent, and there is no alcohol ether solvent or cosolvent, the viscosity at room temperature is 6500-9000mPa·s, and the density is 1.05-1.08g / cm3.

[0033] Specifically, the additive is one or more of leveling agent, film-forming aid, defoaming agent, dispersant, thickening agent and wetting agent.

[0034] The preparation method of the bionic flexible composite drag reduction coating, and the specific steps are as follows:

[0035] Step 1: electronic balance is used to weigh the polymer, and the polymer is slowly added into the beaker containing water under the stirring of cantilever electric mixer, the stirring speed is set to 400r / min, after the polymer is completely added, the curing agent is weighed and added into the beaker, the stirring speed is set to 100r / min, and the stirring is continued for 1h, so that the ring opening reaction of the polymer and the curing agent is fully carried out, and the polymer is grafted onto the curing agent.

[0036] Step 2: electronic balance is used to weigh the water-based epoxy resin emulsion and the additive, and the stirring speed is set to 100r / min, and the stirring is continued for 1h, so that the water-based epoxy resin and the curing agent are uniformly mixed.

[0037] Step 3: the uniformly stirred coating is divided into centrifuge tubes, and the centrifuge is used to remove particles and impurities, and the bionic flexible composite drag reduction coating is prepared.

[0038] The application of the biomimetic flexible composite drag-reducing coating is to apply the biomimetic flexible composite drag-reducing coating on the surface of a vehicle to reduce the drag of the vehicle.

[0039] The above technical solutions are further described below in combination with specific examples:

[0040] Example 1:

[0041] Step 1: 3.5g of a high molecular polymer was weighed using an electronic balance, and was slowly added to a beaker containing 120mL of water under the stirring of a cantilever electric stirrer, the stirring speed of the stirrer was set to 400r / min, after the high molecular polymer was completely added, 5g of a curing agent was weighed and added to the beaker, the stirring speed of the stirrer was set to 100r / min, and the stirring was continued for 1h, so that the high molecular polymer and the curing agent fully underwent ring-opening reaction, and the high molecular polymer was grafted onto the curing agent;

[0042] Step 2: 80g of a water-based epoxy resin emulsion and an additive were weighed using an electronic balance and added to the beaker, the stirring speed of the stirrer was set to 100r / min, and the stirring was continued for 1h, so that the water-based epoxy resin and the curing agent were uniformly mixed;

[0043] Step 3: the uniformly stirred coating was divided into centrifuge tubes, and a centrifuge was used to remove particles and impurities, thereby preparing the biomimetic flexible composite drag-reducing coating.

[0044] Example 2:

[0045] Step 1: 3.5g of a high molecular polymer was weighed using an electronic balance, and was slowly added to a beaker containing 120mL of water under the stirring of a cantilever electric stirrer, the stirring speed of the stirrer was set to 400r / min, after the high molecular polymer was completely added, 5g of a curing agent was weighed and added to the beaker, the stirring speed of the stirrer was set to 100r / min, and the stirring was continued for 1h, so that the high molecular polymer and the curing agent fully underwent ring-opening reaction, and the high molecular polymer was grafted onto the curing agent;

[0046] Step 2: 80g of a water-based epoxy resin emulsion and an additive were weighed using an electronic balance and added to the beaker, the stirring speed of the stirrer was set to 100r / min, and the stirring was continued for 1h, so that the water-based epoxy resin and the curing agent were uniformly mixed;

[0047] Step 3: the uniformly stirred coating was divided into centrifuge tubes, and a centrifuge was used to remove particles and impurities, thereby preparing the biomimetic flexible composite drag-reducing coating.

[0048] Example 3:

[0049] Step 1: Take 3.5g of high molecular polymer with an electronic balance, slowly add the high molecular polymer into a beaker containing 120mL of water under the stirring of a cantilever electric mixer, set the speed of the stirrer to 400r / min, after the high molecular polymer is completely added, take 15g of curing agent and add it into the beaker, set the speed of the stirrer to 100r / min, continue stirring for 1h, so that the high molecular polymer and the curing agent fully undergo ring-opening reaction and the high molecular polymer is grafted onto the curing agent;

[0050] Step 2: Take 80g of water-based epoxy resin emulsion and additives with an electronic balance and add them into the beaker, set the speed of the stirrer to 100r / min, continue stirring for 1h, so that the water-based epoxy resin and the curing agent are uniformly mixed;

[0051] Step 3: The uniformly stirred paint is divided into centrifuge tubes, and a centrifuge is used to remove particles and impurities to obtain a biomimetic flexible composite drag-reducing paint.

[0052] Example Four:

[0053] Step 1: Take 3.5g of high molecular polymer with an electronic balance, slowly add the high molecular polymer into a beaker containing 120mL of water under the stirring of a cantilever electric mixer, set the speed of the stirrer to 400r / min, after the high molecular polymer is completely added, take 20g of curing agent and add it into the beaker, set the speed of the stirrer to 100r / min, continue stirring for 1h, so that the high molecular polymer and the curing agent fully undergo ring-opening reaction and the high molecular polymer is grafted onto the curing agent;

[0054] Step 2: Take 80g of water-based epoxy resin emulsion and additives with an electronic balance and add them into the beaker, set the speed of the stirrer to 100r / min, continue stirring for 1h, so that the water-based epoxy resin and the curing agent are uniformly mixed;

[0055] Step 3: The uniformly stirred paint is divided into centrifuge tubes, and a centrifuge is used to remove particles and impurities to obtain a biomimetic flexible composite drag-reducing paint.

[0056] Example Five:

[0057] Step 1: Take 3.5g of high molecular polymer with an electronic balance, slowly add the high molecular polymer into a beaker containing 120mL of water under the stirring of a cantilever electric mixer, set the speed of the stirrer to 400r / min, after the high molecular polymer is completely added, take 25g of curing agent and add it into the beaker, set the speed of the stirrer to 100r / min, continue stirring for 1h, so that the high molecular polymer and the curing agent fully undergo ring-opening reaction and the high molecular polymer is grafted onto the curing agent;

[0058] Step 2: 80 g of water-based epoxy resin emulsion and additives were weighed with an electronic balance and added into a beaker, the stirring speed of the stirrer was set to 100 r / min, and the stirring was continued for 1 h to uniformly mix the water-based epoxy resin and the curing agent;

[0059] Step 3: The uniformly stirred paint was divided into centrifuge tubes, and a centrifuge was used to remove particles and impurities to obtain the biomimetic flexible composite drag-reducing paint.

[0060] Referring to Figure 2 According to experimental verification, the drag reduction rate of Example Two can reach up to 24%, and the drag reduction rate remains stable at 10% with time scouring; the drag reduction rate of Example One can reach up to 19%, and the drag reduction rate remains stable at 8% with time scouring; the drag reduction rate of Examples Three and Four can reach up to 20%, and the drag reduction rate remains stable at about 8% with time scouring; the drag reduction rate of Example Five can reach up to 15.6%, and the drag reduction rate remains stable at about 5.5% with time scouring. In theory, the drag reduction rate of the coating decreases with the increase of the proportion of the curing agent, but the experimental results show a trend of first increasing and then decreasing. Considering that the curing degree of the coating is low when the content of the curing agent is low, part of the coating will be washed into the flow field, resulting in a decrease in the drag reduction rate. The proportion of the curing agent is not the lower the better, and the appropriate proportion of the curing agent should be selected considering the influence of fluid scouring on the coating to achieve the ideal drag reduction effect.

[0061] Although the embodiments of the present application have been shown and described above, it should be understood that the above embodiments are exemplary and should not be construed as limiting the present application, and those skilled in the art can make changes, modifications, replacements and variations to the above embodiments without departing from the principles and purposes of the present application within the scope of the present application.

Claims

1. A biomimetic flexible composite drag-reducing coating, characterized in that: It comprises waterborne epoxy resin emulsion, high molecular polymer, curing agent, and auxiliary agent, wherein the mass ratio of waterborne epoxy resin emulsion, high molecular polymer, and curing agent is (40-100):(1-20):(5-25); The high molecular polymer is one or more of polyacrylamide, guar gum, tragacanth gum, locust bean gum, and gum arabic. The curing agent is water-soluble modified epoxy polyamine adduct curing agent. The preparation method of the bionic flexible composite drag-reducing coating comprises the following steps: Step 1: slowly add the weighed high molecular polymer into a beaker containing water, and stir until all the high molecular polymer is completely added; then add the weighed curing agent into the beaker, and continuously stir to make the high molecular polymer and the curing agent fully undergo ring-opening reaction, and graft the high molecular polymer onto the curing agent; Step 2: add the weighed waterborne epoxy resin emulsion and auxiliary agent into the beaker, and stir until the waterborne epoxy resin and the curing agent are uniformly mixed; Step 3: divide the uniformly stirred mixture into centrifuge tubes, and use a centrifuge to remove particles and impurities, thereby obtaining the bionic flexible composite drag-reducing coating.

2. The biomimetic flexible drag-reducing coating according to claim 1, characterized in that: The water-based epoxy resin emulsion is a water-based dispersion liquid formed after emulsification treatment with epoxy resin as the main component, which is milky white and uniform fluid with a density of 1.05 g / cm 3 , a VOC content of 0 g / L, and a particle size of ≤ 0.3 μm.

3. The biomimetic flexible drag-reducing coating according to claim 1, wherein: The particle size of the high molecular polymer is 125-170 μm.

4. The biomimetic flexible composite drag-reducing coating of claim 1, wherein: The curing agent is diluted with water, does not contain alcohol ether solvent or cosolvent, and has a viscosity of 6500-9000 at normal temperature , and a density of 1.05-1.08 g / cm 3 .

5. The biomimetic flexible composite drag-reducing coating of claim 1, wherein: The auxiliary agent is one or more of leveling agent, film-forming aid, defoaming agent, dispersing agent, thickening agent, and wetting agent.

6. A process for the preparation of the biomimetic flexible drag reducing coating of any one of claims 1 to 5, characterized in that The specific steps are as follows: Step 1: slowly add the weighed high molecular polymer into a beaker containing water, and stir until all the high molecular polymer is completely added; then add the weighed curing agent into the beaker, and continuously stir to make the high molecular polymer and the curing agent fully undergo ring-opening reaction, and graft the high molecular polymer onto the curing agent; Step 2: add the weighed waterborne epoxy resin emulsion and auxiliary agent into the beaker, and stir until the waterborne epoxy resin and the curing agent are uniformly mixed; Step 3: divide the uniformly stirred mixture into centrifuge tubes, and use a centrifuge to remove particles and impurities, thereby obtaining the bionic flexible composite drag-reducing coating.

7. The process for the preparation of the biomimetic flexible drag reducing coating as claimed in claim 6, wherein: The stirring speed of the high molecular polymer in water is 400 r / min.

8. The process for the preparation of the biomimetic flexible drag reducing coating as claimed in claim 6, wherein: The stirring speed of the curing agent in water containing the high molecular polymer is 100 r / min, and the stirring time is 1 h.

9. The preparation method of the biomimetic flexible composite drag-reducing coating according to claim 6, characterized in that: The stirring speed of the waterborne epoxy resin emulsion and the auxiliary agent after being added into the beaker is 100 r / min, and the stirring time is 1 h.

10. Use of a biomimetic flexible composite drag-reducing coating, characterized in that: The bionic flexible composite drag-reducing coating prepared by the preparation method of claim 6 is brushed on the surface of a vehicle to reduce the drag of the vehicle.

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